Mount Prospect, Illinois 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

338
FXUS63 KLOT 231132
AFDLOT

Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
632 AM CDT Tue Jun 23 2026

.KEY MESSAGES...

- Chance of thunderstorms returns Wednesday, some possibly
  becoming strong in the afternoon. Periodic, but low, chances
  for storms then continue through the end of the week into the
  weekend.

- Turning hotter and more humid into early next week.

&&

.DISCUSSION...
Issued at 229 AM CDT Tue Jun 23 2026

Another dry day is slated for today as surface high pressure
shifts overhead. This will support another day of onshore
northeasterly winds, albeit to a lighter magnitude than those
observed on Monday. Overall, temperatures this afternoon look to
be similar to those observed on Monday, with readings generally
topping out in the upper 70s inland, and in the low 70s near
the Lake Michigan shore.

With our weather remaining quiet today, attention will be
turning to the next mid-level trough/low that will be shifting
eastward across the Dakotas and southern Prairie Providences of
Canada today. This feature, along with an associated surface
low, will move across the western Great Lakes Wednesday into
Thursday. As it does, we can expect our next good chance (50%+)
for scattered showers and thunderstorms Wednesday into Wednesday
evening. The exact timing of these showers and storms remains a
bit unclear, though possibility exists for some remnant showers
and storms to move eastward across southern WI and perhaps
parts of northern IL as early as Wednesday morning. Thereafter,
new scattered showers and thunderstorms appear favorable to
develop in the afternoon and evening, likely in the vicinity of
an approaching cold front.

The environment in which these afternoon thunderstorms develop
looks to be amply sheared, owing to the presence of an enhanced
belt of westerly mid-level flow (45-50 kt) moving out across
the warm sector. Accordingly, a severe potential may accompany
these afternoon thunderstorms, though this will depend largely
on ample destabilization occurring in the wake of the morning
activity. Currently, the SPC has much of southern WI and parts
of northern IL highlighted in a level 1 of 5 severe threat for
Wednesday, which appears appropriate given the kinematic
environment. We will continue to monitor this potential.
Otherwise, the storms are expected to end from west to east
with the passage of the cold front Wednesday evening.

On Thursday into Friday, the surface cold front is expected to
stall out and become west-to-east oriented across downstate IL
and IN as the next surface low sets up across the southern
Plains into the Ozarks. This front is likely to continue to be
the main focus for additional shower and thunderstorm activity
later this week, primarily to our south. However, we cannot
rule out some shower and storm activity working back northward
into areas south of I-80 with the next wave of low pressure
tracking along the frontal boundary on Friday. Otherwise,
temperatures across the area will continue to be a bit below
average, with highs generally in 70s to around 80 (cooler near
the lake) Thursday and Friday.

This weekend into next week, ensemble forecast guidance
continues to be in good agreement with a larger scale weather
pattern change taking place across the central part of the
country. The main feature of this transitioning pattern is
expected to be the development of a subtropical ridge right
across the Mississippi Valley into the Great Lakes into early
next week. Locally, this is expected to result in a turn towards
hotter and more humid weather and an end to the below average
conditions.

KJB

&&

.AVIATION /12Z TAFS THROUGH 18Z WEDNESDAY/...
Issued at 632 AM CDT Tue Jun 23 2026

There are no significant aviation forecast concerns for the
current TAF period.

The presence of surface high pressure in the region will result
in light winds through most of the TAF period, with the
strongest winds today expected to be near 10 kts from a
northeasterly to easterly direction this afternoon at the
Chicago metro terminals behind a sharpening lake breeze. Winds
will take on a southerly direction tomorrow morning and increase
towards 10 kts again as a low pressure system approaches the
area.

The approaching low pressure system and an associated upper-
level disturbance will bring showers and storms to the area
tomorrow. The better chances for this activity affecting the
terminals will come just beyond the end time of the current TAF
period during the afternoon and evening (and during the morning
for RFD), so opted to keep the TAFs dry for now, but some sort
of precipitation and/or storm mention will likely need to be
added in forthcoming TAF packages. If the rain does indeed hold
off through the end of the current TAF period, then VFR
conditions should prevail through the TAF period.

Ogorek

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...None.
IN...None.
LM...None.

&&

$$

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